1. Field of the Invention
This invention relates to accessing a path and more particularly relates to accessing a preferred path through a storage controller.
2. Description of the Related Art
A storage controller is typically employed to connect one or more hosts such as servers, mainframe computers, and the like with one or more storage devices such as hard disk drives, magnetic tape drives, optical storage drives, and the like. The storage controller includes an interconnection module. The interconnection module includes one or more host ports each configured to connect through a first communication channel to the host. In addition, the interconnection module also includes one or more logical devices. Each logical device may emulate a storage device such as a hard disk drive and the like. In addition, each logical device may be comprised of portions of one or more storage devices. The host may connect to and access the logical device through the interconnection module.
The storage controller may include a plurality of redundant interconnection modules. Each interconnection module may connect the host to the logical device. Thus if a first interconnection module fails a second interconnection module may allow the host to connect to the logical device with minimal or no interruption. Each interconnection module may communicate through an internal communication channel with at least one other interconnection module.
The host may request a path to the logical device and be assigned one of the available paths. For example, the host may connect to the logical device through the first interconnection module, the internal communication channel between the first and the second interconnection module, and from the second interconnection module to the logical device. Unfortunately, such a connection between the host and the logical device may have significantly lower performance than a preferred path such as a connection directly from the host through the first interconnection module to the logical device.
From the foregoing discussion, it should be apparent that a need exists for an apparatus, system, and method that connect a host to a logical device through a preferred path. Beneficially, such an apparatus, system, and method would improve the performance of communications between the host and the logical device.